How can you increase performance ?

Question

Hello,
I am building a site but it's framerate is very slow. 
I read some articles that Sprites are much faster then movieclips. 
For example i have 5 long movieclips (4300 pixels in width). These clips scroll in horizontal direction to get a parallax effect.
One of these movieclips contains other movieclips. (all movieclips are not animating and are just graphics).
So I thought to increase performance to convert all movieclips to Sprites as I read that Sprites are better for performance.
I came up with this method:
function castMovieClipToSprite(source:MovieClip, recursive:Boolean = true):void {
     for (var i:int = 0; i < source.numChildren; i++) {
     var child:DisplayObject = source.getChildAt(i) as DisplayObject;
     if (child is MovieClip && recursive) {
     castMovieClipToSprite(MovieClip(child), recursive);
     child = Sprite(child);
But the performance has slightly improved, but if i run the debugger I see that the child objects are still of type MovieClip.
Does anyone know other way to increase performance?
Thanks,
Chris.

Answer 1

I also run some more test and noticed some strange behaviours,
Testlinks:
- Without the gradient ( http://www.rhbmprogress.nl/temp/cs/performanceTest1/ )
- With the gradient ( http://www.rhbmprogress.nl/temp/cs/performanceTest2/ );
Ps. I did not see any difference if I disabled the SWFProfiler so I left it on for test purpuse.
Desktop test,
Firefox version:  4.0.1.
Flash version: 10.2.152.32  (debugger version)
Test1 - > 60 fps
Test2 -> 55 fps
Internet Explorer version: 9.0811.1642
Flash version: 10.3.181.23 (debugger version)
Test1 - >60 fps
Test2 ->55 fps
Other destop computer test:
Firefox version 3.6.13
Flash version: 10.1.52.14 (no debugger)
Test 1-> 58 fps
Test 2-> 35 fps
Internet Explorer version 9.0.8112.1642
Flash version: 10.3.181.23 (no debugger)
Test1-> 60 fps
Test2-> 37 fps
As you can see there are some major difference between flash versions and browser types and versions.
So the solid fill seems to have a stable fps, but the alpha gradient fill does not appear so.
I wonder what flash version you used and what browser type and version